It's been a fruitful time for AMD's CPU team over the last year, with a lot of praise heaped on its current processor product stack. The launch of the new AMD Threadripper 3970X 32-core and the Threadripper 3960X 24-core processors has brought the brand new TRX40 chipset to market, and out of all the motherboard partners, there is a new chipset and 12 new motherboards to dissect. In this article, we'll be analyzing the 12 new boards, which as a priority feature enables a PCIe 4.0 x8 link between the CPU and chipset.

The AMD TRX40 Chipset Overview: PCIe 4.0 For HEDT

One of the most important innovations with AMD's switch to the 7 nm architecture was the inclusion of PCIe 4.0. It marked the first consumer hardware to feature PCIe 4.0, which made a huge talking point during the release of the X570 chipset for the Ryzen 3000 CPUs. For the new HEDT processors, we get a new platform, and AMD's new in-house designed TRX40 chipset also integrates PCIe 4.0. This also comes with a PCIe 4.0 x8 connection between the TRX40 chipset and the new AMD Threadripper 3000 processors, quadrupling the bandwidth compared to any competitor's design.

AMD leveraged GlobalFoundries 14nm to build the TRX40 chipset, which in a maximum I/O configuration, offers 16 downstream PCIe 4.0 lanes for peripherals. Like other AMD chipsets, motherboard vendors can select between these PCIe lanes and additional SATA ports, giving board makers some flexibility between PCIe and storage. Combined with the 56 free lanes from the CPU, motherboard makers have a maximum of 72 PCIe 4.0 lanes to work with in building their motherboards.

Another high point is lots of native support for USB 3.1 G2. Up to 12 USB 3.1 G2 ports are supported at the chipset level - this is a massive jump over X399 which supported just two natively. AMD's TRX40 chipset also has support for four USB 2.0, with extra USB 3.1 G1 available through additional controllers integrated into models. This is why some models opt to use USB 2.0 ports to complement the USB 3.1 G2 on the rear panel where required.

One big aspect motherboard vendors have been focusing on is the power delivery. The two new processors for launch day come in at an impressive 280 W TDP, with the newly announced Threadripper 3990X with 64 cores and 128 threads also having a TDP of 280 W. The motherboards have to be solidly built for these, so it's unlikely we will see something 'cheap' in this market space.

AMD TRX40 and X399 Chipset Comparison
Feature TRX40 X399
PCIe Interface (to peripherals) 4.0 3.0
Max PCH PCIe Lanes 72 66
USB 3.1 Gen2 8 2
Max USB 3.1 (Gen2/Gen1) 12/? 2/14
DDR4 Support 3200 2933
Max SATA Ports 20 12
PCIe GPU Config x16
x16/x16
x16/x8/x16+x8
x16
x16/x16
x16/x8/x16+x4
Memory Channels 4 4
Integrated 802.11ac WiFi MAC N N
Chipset TDP 15 W 5 W
Overclocking Support Y Y

The biggest differences from TRX40 from the previous X399 chipset is the addition of PCIe 4.0 replacing the older PCIe 3.0. This brings extra bandwidth advantages for PCIe devices, such as M.2 drives as the PCIe 4.0 SSD controllers mature. The TRX40 chipset is based on the 14 nm process node from Global Foundries.

The high TDP was one of the caveats of the mainstream X570 chipset, due to the higher power requirements of PCIe 4.0. As a result, motherboard vendors implemented actively cooled heatsinks to help keep the chipset cool. With TRX40, we are in the same ballpark for chipset TDP, however with the beefier CPUs supported, there's going to be a variety of designs. 

A big thing to note is that TRX40 based motherboards do not support the first and second generation Threadripper processors, eg, TR 1950X. TR 2990X. This means the AMD Ryzen Threadripper 3970X, 3960X, and next years Threadripper 3990X are the only models currently compatible with the TRX40 chipset.

AMD SP3 Versus sTR4: Same Number of Pins, Different Layout


SP3 socket pin layout on X399

AMD's transition from PGA to LGA processors at the high-end is a shift that users have gotten used to. Each pin in the socket obviously correlates to power, ground, data, and has to be built as such. Both the SP3 and sTRX4 share the same pin counts, but the move to a wider PCIe 4.0 x8 connection to the chipset has necessitated a fundamental change to socket pin outs in order to compensate. This is why the sockets are incompatible with older processors.


sTR4 socket pin layout on TRX40

AMD states that even though both sockets have the same 'keying' (the plastic bits that stop you installing wrong processors), they have engineered the ID pins such that using a new processor in an old motherboard, or vice versa, will just cause the system not to boot, rather than break it. We're going to take AMD's word for that, rather than potentially break an expensive CPU/motherboard combo.

AMD TRX40 And The Realtek ALC4050HD Audio Codec

All of the twelve TRX40 models at launch include a Realtek ALC1220 HD audio codec (S1220 for ASUS models), but the vast majority of the twelve also include a Realtek ALC4050H codec. We thought this was odd, so reached out to all of the vendors to find out what was going on. Turns out something really interesting.


Realtek ALC1220 and ALC4050H audio codecs on the MSI Creator TRX40

It turns out that AMD did not include any onboard passthough audio in the chipet. That means that all the motherboard vendors that are using a Realtek HD audio codec for the rear audio have had to include the ALC4050H audio codec to bridge the USB to the I2S. The Realtek ALC4050H is used to integrate a bridge between the chipset and USB 2.0 to give the Realtek ALC1220 all the necessary connectivity to the onboard audio. Most of the boards in the stack use the ALC4050H codec to power the 3.5 mm microphone input on the rear panel, as well as the front panel audio as not to waste its capability.

Naturally, we asked AMD about this. The official response from AMD reads

The TRX40 platform does not support the HD audio interface used on most desktop and mobile processors. 

This means that it is down to the vendors to implement a USB audio device (Realtek ALC4050H) to enable use with the HD audio codecs on TRX40 models. 

The TRX40 Product Stack: 12 New Motherboards Unveiled

The launch of both the new Threadripper 3000 series processors, the 3970X and 3960X, has brought about a new wave of models on the new sTR4 socket. There are 12 new TRX40 models in total from the four main vendors, ASRock, ASUS, GIGABYTE, and MSI. It's not just a refresh of the older X399 hardware - the TRX40 chipset is a completely reworked design with many benefits including better componentry, more features from the chipset itself, and most notably, the TRX40 chipset is the first HEDT platform to include PCIe 4.0. 

With more models expected to be announced over the coming months, below is a list of the current TRX40 product stack at launch on the 25th of November:

TRX40 Motherboards Available at Launch (11/25)
Model Size Price
(Amazon)
Price
(Newegg)
ASRock TRX40 Creator ATX - $460
ASRock TRX40 Taichi ATX - $500
 
ASUS ROG Zenith II Extreme E-ATX - $850
ASUS ROG Strix TRX40-E ATX - $550
ASUS Prime TRX40-Pro ATX $450 $450
 
GIGABYTE TRX40 Aorus Xtreme XL-ATX - $850
GIGABYTE TRX40 Aorus Master E-ATX - $500
GIGABYTE TRX40 Aorus Pro WIFI ATX - $400
GIGABYTE TRX40 Designare XL-ATX - $630
 
MSI Creator TRX40 E-ATX $700 $700
MSI TRX40 Pro 10G ATX $500 $500
MSI TRX40 Pro WIFI ATX  - $470

On the next page is a summary of each board's power delivery system, with each subsequent page containing a brief analysis/rundown of all the individual boards.

TRX40 Power Delivery Specifications & Comparison
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  • jeremyshaw - Friday, November 29, 2019 - link

    Since the last page has a picture of the chipset saying Made in Taiwan, it's probably either TSMC or UMC... unless if packaging somehow counts as "made in." Reply
  • msroadkill612 - Friday, November 29, 2019 - link

    Good spotting & there may be more to t than u think.

    Dunno, but others may?

    I recall reading that the exciting new IO chip on Zen 2, & the TR chipset, are ~"cut an pastes" of each other - one is made by tsmc & the other by glofo.

    This may be the source of the confusion?
    Reply
  • Bccc1 - Thursday, November 28, 2019 - link

    Thanks for this writeup. I'm currently drawn to Gigabytes TRX40 Designare and TRX40 Aorus Xtreme. Does the "40GB/s GC-Titan Ridge add-in card" work on any board?

    Any info on bifurcation support? Gigabyte is quite clear about that and offers x4x4x4x4 for the x16 slots and x4x4 for the x8 slots. Sadly no 8x4x4 or x8x8. MSIs manual explains the BIOS option "PCIe SlotX Lanes Configuration" with the sentence "PCIe lanes configuration for MSI M.2 XPANDER series cards/ Other M.2 PCIe
    storage card." which sounds like x4x4x4x4 bifurcation to me, but is quite vague.
    Is x8x8 and x8x4x4 supported on any board?
    Reply
  • msroadkill612 - Friday, November 29, 2019 - link

    Bifurcation obfuscation? Reply
  • eek2121 - Friday, November 29, 2019 - link

    I can't speak to the current MSI offerings, but my x399 Gaming Carbon (off the top of my head, I don't use this feature, however) supports x4x4x4x4 and x8x8. Other modes may be possible, but I haven't looked. Reply
  • The_Assimilator - Thursday, November 28, 2019 - link

    Making a CPU that fits in a socket but doesn't work in it is idiotic. Especially considering the target market, did AMD really need to save a few pennies on getting Lotes to make slight modifications to their TR3 tooling? Reply
  • Spunjji - Friday, November 29, 2019 - link

    "Especially considering their target market"

    System integrators, enthusiasts and experts?
    Reply
  • yetanotherhuman - Friday, November 29, 2019 - link

    All of them have fans. Bleh. I remember chipset fans. No thanks. X570 is a piece of shit to me for the same reason (apart from that one gigabyte board that costs way too much). Reply
  • jeremyshaw - Friday, November 29, 2019 - link

    Also one Asrock board which costs even more! Reply
  • Korguz - Friday, November 29, 2019 - link

    all be cause of a chipset fan ?? thats borderline crazy, have you even heard them ? chances are, the other fans in your case would drown it out and you wouldnt even hear it Reply

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